Abstruce Posted February 10, 2006 Author Report Share Posted February 10, 2006 Wow those electrons sure do look blurry!!!! :hihi: Ok, if you want to get technical about it, all the atoms in every photograph are in motion. Quote Link to comment Share on other sites More sharing options...
InfiniteNow Posted February 10, 2006 Report Share Posted February 10, 2006 In all of my effort to figure out how a series of individually fired photons will create an interference pattern, and how that pattern goes away if you observe through which slit the photon passed... I forgot to thank you, Abstruce, for posting the really cool cartoon on the first post of the thread. Cheers. :hihi: Quote Link to comment Share on other sites More sharing options...
Abstruce Posted February 11, 2006 Author Report Share Posted February 11, 2006 In all of my effort to figure out how a series of individually fired photons will create an interference pattern, and how that pattern goes away if you observe through which slit the photon passed... I forgot to thank you, Abstruce, for posting the really cool cartoon on the first post of the thread. Cheers. :hihi: I do not know the answers, I am just trying to use my imagination to understand the force of everything I.e. (Gravity, Strong Nuclear Force). I know in my heart the double slit experiment has something to tell us about the mystery of nature. This is where my interest are, I know that once we truly understand this mystery it will be a pivotal point in the evolution of mankind. Not even the advent of the light bulb will compare to the impact of this technowledge. I know that Albert Einstein tried to his dying day, understand this phenomena. If he were alive today, I think he would say," To solve the equation for Gravity, You must not let the force of fundamentalism hold you down." Science and Religion both have strong elements of fundamentalism, this is a travesty and it violates every essence of my common sense. I can only say, when one fails to Dream or Imagine they loose their ability to explore the unknown. Quote Link to comment Share on other sites More sharing options...
EWright Posted February 11, 2006 Report Share Posted February 11, 2006 http://en.wikipedia.org/wiki/Double-slit_experimentThe double-slit experiment consists of letting light diffract through two slits producing fringes on a screen. These fringes or interference patterns have light and dark regions corresponding to where the light waves have constructively and destructively interfered. The experiment can also be performed with a beam of electrons or atoms, showing similar interference patterns; this is taken as evidence of the "wave-particle duality" predicted by quantum physics. Note, however, that a double-slit experiment can also be performed with water waves in a ripple tank; the explanation of the observed wave phenomena does not require quantum mechanics in any way. The phenomenon is quantum mechanical only when quantum particles, such as atoms or electrons, manifest as waves. I find it interesting that this experiment works with ATOMS as well as light waves and electrons. Do we now consider atoms to exhibit a wave-particled duality just as the photon is believed to? Perhaps this experiment should raise the question once again of whether photons travel as a wave at all, or if we're just not reading between the (interference) lines. Quote Link to comment Share on other sites More sharing options...
Erasmus00 Posted February 11, 2006 Report Share Posted February 11, 2006 http://en.wikipedia.org/wiki/Double-slit_experiment I find it interesting that this experiment works with ATOMS as well as light waves and electrons. Do we now consider atoms to exhibit a wave-particled duality just as the photon is believed to? Perhaps this experiment should raise the question once again of whether photons travel as a wave at all, or if we're just not reading between the (interference) lines. The fact that EVERYTHING (atoms, photons, electrons, etc) exhibits this wave nature is at the very heart of quantum mechanics. In fact, classical mechanics is nicely derivable from quantum. The double slit experiment, far from prompting us to raise the question of whether photons travel as a wave, should reassure us that they do. -Will Quote Link to comment Share on other sites More sharing options...
adc Posted February 12, 2006 Report Share Posted February 12, 2006 I have probably read a dozen books on QM in the past 5 years (after retiring-nothing to do :hihi: ). Unfortunately I'm not up to the math. Jim Al- Kalli in his book "Quantum-A Guide for the Perplexed" Explains it as goood as I have seen: The nature of particles and waves is that their location at any point in time can be described by a wave function equation, which can be described as waves of probability-(nothing new here). No one really knows how the Particle/photon travels-the wave function just works when it is transit. When the wave function encounters two slits it divides into two wave functions (again its not what physically occurrs-just what determines position in space). On the other side of the slits each piece of wave function spreads out again (like wave functions do). When the particle strikes the screen it strikes it in accordance with the probable nature of its location given by the wave function (s). Presumably the location will appear as per the interference of the two spread out wave patterns. There will be no strikes where the function says there shouldn't be. Sorry if I botched up my first post. Al-Khali describes it much better. And he probably didn't just finish a glass of wine. BTW two other books which were pretty good (for me) were Gerard't Hooft "In Search of Ultimate Building Blocks" and Kenneth Ford, "The Quantum World" InfiniteNow 1 Quote Link to comment Share on other sites More sharing options...
EWright Posted February 12, 2006 Report Share Posted February 12, 2006 The fact that EVERYTHING (atoms, photons, electrons, etc) exhibits this wave nature is at the very heart of quantum mechanics. In fact, classical mechanics is nicely derivable from quantum. The double slit experiment, far from prompting us to raise the question of whether photons travel as a wave, should reassure us that they do. -Will Perhaps you can expand on this further, Will. I don't see why it should *reassure* me that photons are waves, if particles exhibit the same phenomenon. Quote Link to comment Share on other sites More sharing options...
InfiniteNow Posted February 12, 2006 Report Share Posted February 12, 2006 Another tough point around which to wrap our thoughts is how the interference pattern goes away if you observe the slits to verify through which the particle passes. You look to see if it went through slit A or slit B, and notice it went through slit A (not both as the interference pattern lends suggestion)... then the interference pattern goes away. You are left with a negative silhouette of two slits on the screen. (i.e. two bands of light on an otherwise dark screen) Quote Link to comment Share on other sites More sharing options...
Erasmus00 Posted February 12, 2006 Report Share Posted February 12, 2006 Perhaps you can expand on this further, Will. I don't see why it should *reassure* me that photons are waves, if particles exhibit the same phenomenon. Quantum theory doesn't stop at photons. It suggests ALL particles are waves. Electrons, neutrons etc should behave exactly as photons do. And they do. The theory matches the predictions. -Will Quote Link to comment Share on other sites More sharing options...
EWright Posted February 13, 2006 Report Share Posted February 13, 2006 Quantum theory doesn't stop at photons. It suggests ALL particles are waves. Electrons, neutrons etc should behave exactly as photons do. And they do. The theory matches the predictions. -Will Ah, I see... I also see I have some reading on quantum theory to do. Thanks Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted February 13, 2006 Report Share Posted February 13, 2006 Wave........... Strictly, like many things in physics nowadays, this is really just an old habit of speach. Quantum formalism basically sums over complex amplitudes to give a total amplitude; the modulus square of this giving the probability density of something. Very often the phases are the most determining thing in the summation, as for the case of the alternately constructive and destructive interference patterns. These amplitudes can be viewed as a sort of meta-reality amongst which an outcome may be determined. The electromagnetic field can be described by different paths between the same two points giving different phase differences if you travel along one or the other and a more complicated but analogous thing holds for other forces. Why, then, do we say waves? Initially people basically reasoned on the distributions of position, calculating the corresponding amplitudes, using Schrödinger's equation in terms of position and matched it all up with observed spectroscopic data etc... The "wave" is just simply the position amplitude as a function of space and time or, if you prefer, the spatial distribution propagating in time. It's a special case of the formalism. Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted February 13, 2006 Report Share Posted February 13, 2006 Another tough point around which to wrap our thoughts is how the interference pattern goes away if you observe the slits to verify through which the particle passes. You look to see if it went through slit A or slit B, and notice it went through slit A (not both as the interference pattern lends suggestion)... then the interference pattern goes away.True, if the bugger interacts with something that enables the distinction to be made, its state will not be one that leads to the interference pattern. If an interaction makes it possible to say it's more likely (say, 83%) it went through hole A then the probability distribution will be more or less like either extreme case, according to the above probability that can be calculated. This very neatly avoids the paradox: if I'm sure it went through hole A, why should B count a t all? This is actually what illustrates that, if we see the interference, there's no point in even posing the question as to which hole it went through.:hihi: Yup!!!! In a sense still not universally agreed upon, it went through both! Bohm disagrees with this and provides an intuitive alternative, but his guiding-wave equation doesn't really avoid the paradox. Quote Link to comment Share on other sites More sharing options...
InfiniteNow Posted February 13, 2006 Report Share Posted February 13, 2006 Bohm disagrees with this and provides an intuitive alternative, but his guiding-wave equation doesn't really avoid the paradox.True, it does not avoid the paradox. The Bohm Interpretation has a lot going for it, and also some negative aspects, but I like that it's something different that's not just fluff. Unfortunately, it does nothing for me in terms of the interference pattern going away if you know through which slit the particle passed... Wiki says this:For example, in the Double-slit experiment for electrons, each electron just travels through only one slit, but the wave function causes the interference pattern. That answer doesn't satisfy me at all. Maybe I'm just being too rigid? Am I the only one who thinks this explanation is incomplete? Quote Link to comment Share on other sites More sharing options...
Abstruce Posted February 14, 2006 Author Report Share Posted February 14, 2006 The fact that EVERYTHING (atoms, photons, electrons, etc) exhibits this wave nature is at the very heart of quantum mechanics. -Will Very interesting, not that it matters, but I question this assumption.:eek2: The hart of the quantum world seems to be the vortex. This is evident in super colliders when the sub-atomic particles are in motion after colliding they tend to spin up into a vortex. The Vortex exist in the macro and the cosmic dimensions as well (tornados, Black Holes) They are the direct result of Gravity and the Strong Nuclear Force. Am I wrong? Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted February 14, 2006 Report Share Posted February 14, 2006 This is evident in super colliders when the sub-atomic particles are in motion after colliding they tend to spin up into a vortex.I suspect you've seen images from bubble chambers or other apparatus where a magnetic field is used to determine the charge/mass ratio. Similar effects are used for plasma confinement and are behind the Foucault currents that cause loss in trasformers or other AC devices with magnetic windings. Quote Link to comment Share on other sites More sharing options...
repeater Posted February 28, 2006 Report Share Posted February 28, 2006 Hello I've got a question In the electron slit experiment:Electrons are fired one at a time through a double slit. An interference pattern appears after some time. Now if I fire an electron, point particle, I'd fire it straight at the centre of the double slit. None would get through that piece of cardboard! It seems to me that uncertainty to the electron's movement would perhaps be determined by the firing device? Oh well, I'm sure the scientists thought of that :hyper: Quote Link to comment Share on other sites More sharing options...
arkain101 Posted February 28, 2006 Report Share Posted February 28, 2006 yah its particle wave duality madness :hyper: Quote Link to comment Share on other sites More sharing options...
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